§ Задание 138
\[\boxed{\mathbf{1.}\mathbf{138}}\]

\[\textbf{а)}\ B = \left\{ 10;20;30;40;50 \right\}\]
\[\textbf{б)}\ B = \left\{ 5;15;25;35;45 \right\}.\]
\[\textbf{в)}\ B = \left\{ 5 \right\}.\]
\[\textbf{г)}\ B = \left\{ \varnothing \right\}.\]
\[\boxed{\mathbf{1.}\mathbf{138}}\]

\[\textbf{а)}\ B = \left\{ 10;20;30;40;50 \right\}\]
\[\textbf{б)}\ B = \left\{ 5;15;25;35;45 \right\}.\]
\[\textbf{в)}\ B = \left\{ 5 \right\}.\]
\[\textbf{г)}\ B = \left\{ \varnothing \right\}.\]